Goals set for current year: (1) To study the mannosylretinyl phosphate- like compound isolated from chick embryo fibroblasts which is similar in most (but not all) properties to mannosylretinyl phosphate (MRP) made enzymatically from retinyl phosphate and GDP-mannose; to study the transfer of mannose to exogenous protein acceptors from MRP and the MRP-like compound; (2) To modify the serum alpha 1-macroglobulin, the serum protein affected by vitamin A deficiency, so as to act as an in vitro mannose acceptor from MRP; to study the relation between vitamin A deficiency and the serum level of the alpha 1-macroglobulin by means of a radioimmunoassay; (3) To identify the water-soluble urinary metabolite of vitamin A associated with a urinary peptide and to determine its relation to vitamin A depletion.